Case Study

Literature

Dartington Primary School, Devon

An innovative dry floor screed from Knauf Drywall boosts the green credentials of new and highly sustainable primary school buildings under construction in the Devon countryside, near Totnes. About 1,800m2 of thermally transparent Knauf Brio Dry Floor Screed was specified for the new Dartington C.E. Primary and Nursery School, to ensure maximum efficiency from its underfloor heating, from specialist supplier Nu-Heat. Knauf Brio is a gypsum fibre board, specially developed for new or refurbishment flooring and for use with underfloor heating or cooling systems.

The new buildings, due for completion at the end of 2009, will replace outdated accommodation nearby with purpose built modern facilities in a sustainable learning environment to reinforce the school’s ethos. Designed by Bristol-based architectural practice White Design, the new school consists of four clusters of single storey buildings – three are sets of teaching spaces, grouped by age, while the fourth contains communal facilities such as the sports hall, offices, staff room, plant room and music room.

The school is built almost exclusively of prefabricated timber panels and other wood products, all from sustainable sources. Buildings are designed to make maximum use of natural light, water and energy. Apart from the sports hall which has a sprung timber floor, all other rooms have Knauf Brio on top of Nu-Heat underfloor heating installations powered by air source heat pumps and solar energy.

Nu-Heat Product Development Manager Mark Millett says: “We recognised the benefit of partnering with Knauf Drywall, because Knauf Brio is an excellent complement to our system. It conducts heat well, and that means we need lower temperatures in the underfloor pipes, which is ideal when you are working with heat pumps. Knauf Brio also has good comfort and acoustic benefits.”

Project architect Andrew Docherty says Knauf Brio was specified for its thermal transparency – which enhances the efficiency of the heating system – and because it provides an excellent, durable surface for carpeting or other finishes. “It also avoids the need for a conventional wet screed, which means the contractor, Interserve, will be able to complete this project without any wet trades on site during construction – even the concrete foundations were cast off site,” he says.

Non-combustible Knauf Brio boards are simple and fast to lay, requiring no special skills for a perfect job. The 600mm x 1,200mm boards are laid directly over underfloor heating and cooling systems – typically where the pipe array is installed in metal diffuser trays over moulded insulation. The precise tiered edges are glued with Knauf Brio Joint Adhesive, and screwed together to ensure a solid bond. The new floor can take traffic as soon as the glue has hardened, normally in just a few hours.

Knauf Brio boards are 18mm or 23mm thick, offering great strength without impeding the transfer of heat energy. Temperature changes in the room above are felt almost immediately and coupled with the greater comfort of underfloor systems’ uniform space heating, less heating energy is required. As a result, where underfloor systems are powered by conventional boilers, Knauf Brio helps to reduce fuel costs and CO2 emissions.

Ideal for laying over virtually any new or existing subfloor, Knauf Brio is the perfect solution for retro-fit underfloor heating systems. With a combined thickness of 50mm, it has minimal impact on overall room height – and it does not impose any significant additional structural load.

Knauf Drywall also offers Brio with a 10mm wood fibre laminate on its underside, providing enhanced acoustic performance where the board is used, for example, in the upper floors of houses.